Isolation and characterization of an extracellular protease-esterase and an intracellular serine protease are underway. Immunological studies indicate these are non-identical. The substrate specificity and kinetic properties of the latter enzyme is being studied. The effect of phosphonic acid derivatives on the intracellular serine protease is being investigated; these inhibitors will be tested in vivo. The mode of action of the benzeneboronic acids in blocking sporulation and the appearance of the intracellular serine protease is also being studied. Reaction at the cell surface is implicated at this point. BIBLIOGRAPHIC REFERENCES: Effect of Benzeneboronic Acids on Sporulation and on Production of Serine proteases in Bacillus subtilis Cells. G. Geele, E. Garrett and J.H. Hageman. Spores VI. P. Gerhardt, R.N. Costilow and H.L. Sadoff, eds. p. 391 A.S.M. (1975). Use of N-Benzoyl-L-tyrosine Thiobenzyl Ester as a Protease Substrate. D.A. Farmer and J.H. Hageman, J. Biol. Chem. 250, 7366 (1975).